Gibson et al, U.S. Pat. No. 3,957,583, discloses a process and apparatus for conducting antibiotic susceptibility tests in a relatively short time. In U.S. Pat. No. 3,957,583, the clinical specimen is examined directly without isolating the suspected microorganisms. The basic process of U.S. Pat. No. 3,957,583 involves introducing a specimen into blends of a selective culture medium and known antimicrobial agents. If the specimen contains a microorganism which is favored by the culture medium of the blend, and the microorganism is not susceptible to the antibiotic, the optical characteristics of the blend will change.
It is an object of the present invention to provide a culture medium in which the sensitivity and resistance to known antibiotics of Klebsiella and Enterobacter microorganisms is demonstrated with a high degree of precision.
The major problem encountered with conventional microbial sensitivity tests is the length of time that passes from obtaining a clinical specimen from the patient to selection of a suitable antimicrobial agent that can be expected to control any microorganisms detected. Application Ser. No. 682,659 (now U.S. Pat. No. 4,072,571 issued Feb. 7, 1978) discloses a medium for detecting Klebsiella/Enterobacter microorganisms for a given set of antibiotics.
Also the medium of U.S. Pat. No. 4,072,571 contains ingredients which are detrimental to certain antibiotics. Thus, the medium of the present invention is designed not only to facilitate growth of Klebsiella and Enterobacter but also to retain and enhance the effectiveness of antibiotics, so that one can get an accurate reading of the potency of a particular antibiotic against the Klebsiella and Enterobacter organisms.
Accordingly, it is an object of the present invention to provide a medium which, when used with the apparatus described in U.S. Pat. No. 3,957,583, will allow a clinician to determine within a relatively short period of time (from about 8 to about 12 hours) which of a series of antimicrobial agents will be effective in suppressing the activity of infectious microorganisms.
The broth of the present invention will allow the clinician to test several antibiotics simultaneously to determine the Klebsiella and Enterobacter sensitivity of each. The results obtained allow the clinician to select a backup antibiotic, should the primary antibiotic fail to treat the patient's condition.